Quantity risk analysis of gas dispersion for chemical facility

The leakage and dispersion risk of certain chemical facility was always difficult to evaluate quantitatively because of the existing of many uncertain parameters in evaluation models. For this reason, taking weather data of Nanjing and some other cities as data sources, STATISTICA 6.0 was used to study the distribution of wind speed, humidity, air temperature and cloud cover rate, etc. And their respective distribution functions were proposed. The distributions of leakage orifice area and leakage orifice direction were also analyzed and reasonable distribution functions were gotten. As a widely used software package for leakage and dispersion, HGSYSTEM was chosen to unite Monte-Carlo method to form a quantity risk analysis method for chemical facilities. An accessory pipe (φ20 cm) of a propane tank (normal temperature, high pressure) was taken as a demo, and the influencing distances of two cloud blocks, with the concentration of 2.1% (lower explosion limit) and 0.0153% (Russia MAC), were calculated for different cumulative probability, among which, when the cumulative probability is 95%, the two distances are respectively 69.7 m and 2764 m.